RESUMO
The bias of A-rich codons in HIV-1 pol is thought to be a record of hypermutations in viral genomes that lack biological functions. Bioinformatic analysis predicted that A-rich sequences are generally associated with minimal local RNA structures. Using codon modifications to reduce the amount of A-rich sequences within HIV-1 genomes, we have reduced the flexibility of RNA sequences in pol to analyze the functional significance of these A-rich 'structurally poor' RNA elements in HIV-1 pol. Our data showed that codon modification of HIV-1 sequences led to a suppression of virus infectivity by 5-100-fold, and this defect does not correlate with, viral entry, viral protein expression levels, viral protein profiles or virion packaging of genomic RNA. Codon modification of HIV-1 pol correlated with an enhanced dimer stability of the viral RNA genome, which was associated with a reduction of viral cDNA synthesis both during HIV-1 infection and in a cell free reverse transcription assay. Our data provided direct evidence that the HIV-1 A-rich pol sequence is not merely an evolutionary artifact of enzyme-induced hypermutations, and that HIV-1 has adapted to rely on A-rich RNA sequences to support the synthesis of viral cDNA during reverse transcription, highlighting the utility of using 'structurally poor' RNA domains in regulating biological process.
Assuntos
DNA Complementar/biossíntese , DNA Viral/biossíntese , Genes pol , HIV-1/genética , RNA Viral/química , Sequências Reguladoras de Ácido Ribonucleico , Transcrição Reversa , Adenina/análise , Sequência de Bases , Linhagem Celular , Códon , Dimerização , HIV-1/fisiologia , Humanos , Conformação de Ácido Nucleico , Proteínas Virais/metabolismo , Vírion/metabolismo , Internalização do Vírus , Replicação ViralRESUMO
The magnitude and durability of immune responses induced by replication-defective adenovirus serotype 5 (ADV5) vector-based vaccines were evaluated in the simian-human immunodeficiency virus/rhesus monkey model. A single inoculation of recombinant ADV5 vector constructs induced cellular and humoral immunity, but the rapid generation of neutralizing anti-Ad5 antibodies limited the immunity induced by repeated vector administration. The magnitude and durability of the immune responses elicited by these vaccines were greater when they were delivered as boosting immunogens in plasmid DNA-primed monkeys than when they were used as single-modality immunogens. Therefore, administration of ADV5-based vectors in DNA-primed subjects may be a preferred use of this vaccine modality for generating long-term immune protection.
Assuntos
Adenovírus Humanos/imunologia , Anticorpos Antivirais/sangue , Vetores Genéticos/imunologia , Infecções por HIV/imunologia , Imunização Secundária , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Linfócitos T/imunologia , Vacinação , Vacinas Virais/imunologia , Vacinas contra a AIDS/administração & dosagem , Vacinas contra a AIDS/imunologia , Proteínas E1 de Adenovirus/genética , Proteínas E3 de Adenovirus/genética , Adenovírus Humanos/genética , Animais , Avaliação Pré-Clínica de Medicamentos , Deleção de Genes , Vetores Genéticos/genética , Anticorpos Anti-HIV/sangue , HIV-1/genética , HIV-1/imunologia , Injeções Intramusculares , Macaca mulatta , Testes de Neutralização , Plasmídeos/genética , Síndrome de Imunodeficiência Adquirida dos Símios/sangue , Vírus da Imunodeficiência Símia/genética , Vírus da Imunodeficiência Símia/imunologia , Vacinas de DNA/administração & dosagem , Vacinas de DNA/imunologia , Vacinas Virais/administração & dosagemRESUMO
A new collaborative model of research is needed to increase resources, to prioritize the R (ii) to increase the pace, reduce the overlap, and more systematically explore the elements of and delivery systems for vaccines; (iii) to use common standards for the prompt comparative testing of vaccine candidates; (iv) to expand resources for manufacturing vaccine candidates to speed their use in human trials; and (v) to increase the capacity for international clinical trials and to focus this effort toward quickly measuring the effectiveness of vaccine protection as prototype vaccine candidates are identified.